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Epsilon Apodis

Epsilon Apodis
Diagram showing star positions and boundaries of the Apus constellation and its surroundings
Cercle rouge 100%.svg

Location of ε Apodis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Apus
Right ascension 14h 22m 23.16467s
Declination –80° 06′ 32.2053″
Apparent magnitude (V) 5.06
Characteristics
Spectral type B3 V
U−B color index –0.610
B−V color index –0.121
Variable type γ Cas
Astrometry
Radial velocity (Rv) +4.5 km/s
Proper motion (μ) RA: –9.51 mas/yr
Dec.: –14.34 mas/yr
Parallax (π) 5.06 ± 0.22mas
Distance 640 ± 30 ly
(198 ± 9 pc)
Details
Mass 6.15 ± 0.71 M
Radius 3.9 R
Luminosity 1,614 L
Surface gravity (log g) 4.18 cgs
Temperature 17,050 K
Metallicity [Fe/H] –0.02 dex
Rotational velocity (v sin i) 255 km/s
Age 38.3 ± 4.4 Myr
Other designations
CD–79 559, HD 124771, HIP 70248, HR 5336, SAO 257142.
Database references
SIMBAD data

Epsilon Apodis (ε Aps, ε Apodis) is the Bayer designation for a star in the southern circumpolar constellation of Apus. It has an apparent visual magnitude of 5.06, which is bright enough to be viewed from dark suburban skies. Based upon parallax measurements, it is at a distance of roughly 640 light-years (200 parsecs) from Earth.

Based upon a stellar classification of B3 V, this is a massive, B-type main sequence star that is generating energy through the fusion of hydrogen at its core. Epsilon Apodis has more than six times the mass of the Sun and nearly four times the Sun's radius. It is radiating 1,614 times as much luminosity as the Sun from its outer envelope at an effective temperature of 17,050 K. At this heat, it has a blue-white glow that is a characteristic of B-type stars.

It is spinning rapidly, with a projected rotational velocity of 255 km/s giving a lower bound for the azimuthal velocity along the equator. Epsilon Apodis is classified as a Gamma Cassiopeiae typevariable star and its brightness varies between magnitudes 4.99 and 5.04.

In Chinese caused by adaptation of the European southern hemisphere constellations into the Chinese system, 異雀 (Yì Què), meaning Exotic Bird, refers to an asterism consisting of ε Apodis, ζ Apodis, ι Apodis, β Apodis, γ Apodis, δ Octantis, δ1 Apodis, η Apodis and α Apodis. Consequently, ε Apodis itself is known as 異雀九 (Yì Què jiǔ, English: the Ninth Star of Exotic Bird.)


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